Peroxy-substituted persulfonates



i atentecl Dec. 26, 1950 2,536,008 r noxv-s es'rrrU'rED PERSULFONATES Frederick F. Rust, Qakland, and Alan R. Stiles and William E. Vaughan, Brkeley,0alif., assignors to Shell Development Company, San Franciscmxflalifl, a corporation of Delaware No Drawing. ApplicationFebruary 21,, 1949,

Serial No. 77,693

'7 Claims. 1

This invention relates to estersof persulfonic acids in which one or more persulfo groups (--SO2-OO-H) replace hydrogen atoms of an organic peroxide. The invention provides a series of valuable new compounds, a particularly versatile class of which are the tertiary-hydrocarbon esters of persulfonic acids in which a persulfo group replaces a hydrogen atom of a ditertiary-hydrocarbon peroxide, or of its hal nanalog containing one; or more chlorine or bromine atoms.

This application is a continuation-impart of our copending application Serial No. 792,840, filed December 19, 194,7 and now Patent No. 2,519,403 issued August 22, 1950. our, earlier filedapp tion describes and claims a novel reaction process by which certain organic peroxides can be sulfohalogenated to form the novel peroxidic sulionyl halides, which are also described and claimed therein. This application described and claims the class of novel compounds which can be prepared by contacting such sulfonyl halides with a salt of a hydroperoxide under conditions conducive to the precipitation of inorganic salt. However, like any other organic compounds, the compounds provided by the present invention can be synthesized by other methods.

In general, the --O-O grouping in an organic molecule is so unstable that a compound containing it, if it reacts under a given set of conditions, undergoes a reaction involving the bonds of this grouping. We have now discovered, however, that when the grouping iscontained between two tertiary carbon atoms, not only can the compound be sulfohalogenated, but derivatives of the sulfonyl halide can be formed, and such derivatives exhibit both the chemical properties characteristic of the derivative and of the particularly stable class of peroxides.

l 1e compounds provided by the invention are peroxides, having the formula R-OO--R where each R is an organic radical the first atom of which (the atom attached to oxygen) is a saturated carbon atom (linked to four other atoms by single bonds), in which peroxide at least one hydrogen atom is replaced by a group having the formula SO2COR where R is an organic radical the first atom of which is a saturated carbon atom. These compounds are polyfunctional and exhibit the properties characteristic of organic peroxides of the, formula R-O-O-.R as well as properties characteristic of esters of persulfonic acids. They are particularly valuable in that they provide. a meansrof greatly extending the. existing; knowledge of;

peroxidic compounds, and make available compounds containing two groupshavlng totally different structures and properties, both of which are thermally decomposable into organic free radicals. In additionto their direct, commercial value as initiators of free radical reactions (illus-- trated by the fact that the presence of a small amountof tertiary-butyl 2-tertiary-butylpe1'oxy- 2-methylpropanepersulfonate in a suspension of vinyl chloride under conditions conducive to a peroxide initiated polymerization, resulted in the ,iormation of polyvinyl chloride), these compounds are peroxi'dic materials of a structure totally different 'from any peroxidic materials heretofore known and. provide one means of extending the existing knowledge about peroxidic materials.

Examplesof the compounds provided by the invention include aliphatic compounds such .as ethyl 2-tertiary-butyl-zrmethylepropanepersulfonate, bis(tertiary butylperoxysulfo tertiarybutyDperoxide, and l-methylcyclohexyl Z-tertiary-amylperoxy- 2 methylbutanepersulfonate; aromatic compounds such as ethyl 2-(a,,a-dimethylbenzylperoxy) -2- phenylpropanepersulfonate, tertiary-,butyl 2-tertiary-amylperoxy-2 phenylpropanepersulfonate and a,a,- dimethyb benzyl 2-tertiary-butylperoxy-2-methylpropanepersulfonate; and halogen-containing compounds such as chloro-tertiary-butyl 2-(chloro -tertiarybutylperoxw 2 methylpropanesulfonate; l methylcyclohexyl 2-tertiary-amylperoxy-Z-chloromethylbutanesulfonate and propyl Z-(bromotertiary-butylperoxy) -2 methylpropanesulfonate.

The preferred method. of producing the compounds provided by the inventioncomprises-sulfachlorinating: a peroxide having the formula where R is a tertiary-hydrocarbonradical or its halogen-analog containing one or more chlorine or bromine. atom-s. We have found that this method of-usynthesis the following: equations il- .-lustrated by the reactions seminars-mp 3 peroxide and the sodium salt of tertiary-butyl hydroperoxide, using, in each case, equivalent amounts of the reactants) express substantially the only reactions by which the reactants are converted:

actinic light (CHa)sCOO-C(CHa)2-CH2SO2C1 H01 (OHa)zCO-()Na Because of their complex structure, names of the compounds provided by the invention do not convey a clear picture of the various molecules to the reader. Illustrative examples of the preferred class of such compounds, tertiary-hydrocarbon (or their halogen-analogs containing one or more atoms of chlorine or bromine) esters of persulfonic acids in which a persulfo group replaces a hydrogen atom of a di-tertiary-hydrocarbon peroxide or of its halogen-analog containing one or more chlorine or bromine atoms,

.are more clearly represented as the reaction prodnets of the monosulfochlorination products of the peroxides, including the following, with salts of hydroperoxides, including the following: tertiary-butyl peroxide, bis(ch1oro-di-tertiarybutyl) peroxide, di-tertiary-amyl peroxide, .bromo-tertiary-amyl tertiary-butyl bis(a,a.-dimethylbenzyl) peroxide (cumene peroxide) and bis(1-methylcyclohexyl) peroxide re- .acted with the sodium salt of tertiary-butyl hydroperoxide, tertiary-amyl hydroperoxide, bromotertiary-butyl hydroperoxide, a,a-dimethylbenzyl hydroperoxide, para-chloro-a,-a-dimethylbenzyl hydroperoxide, and l-methylcyclohexyl hydroperoxide.

The tertiary-alkyl esters of persulfonic acids in which a persulfo group replaces a hydrogen atom of a di-tertiary-alkyl hydroperoxide comprise a particularly preferred group of compounds provided by the invention.

The following examples illustrate in detail methods by which particular peroxy-substituted persulfonates can be produced. As many variations in the reactants and reaction materials are within its scope, the invention is not to be construed as limited to the particular compounds specified in the examples or to the materials produced by the particular reactions described therein.

Example I A sulfonyl chloride suitable for conversion to a persulfonate provided by the present invention, is prepared by the following procedure. In a transparent reaction vessel 146 grams (1.0 mole) of di-tertiary-butyl peroxide is illuminated by a 500 watt lamp and maintained at from 6 C. to 80 C. A gaseous mixture of 0.3 mole of sulfur dioxide with 0.2 mole of chlorine is introduced over a period of 1.5 hours. The crude Z-tertiary-butylperoxy-Z-methylpropane sulfonyl chloride is isolated by distilling off the dissolved gases and unreacted peroxide.

Example II Tertiary-butyl 2-tertiary-butylperoxy-2-methylpropanepersulfonate is produced by dissolving 5 grams of tertiary-butyl chlorosulfonyl-tertiarybutyl peroxide in cc. of ether and adding the resulting solution to 5 grams of the sodium salt of tertiary-butyl hydroperoxide suspended in cc. of ether while maintaining the reactants, during the mixing at 1 The persul onate is solated peroxide,

4 by extracting the reaction mixture with water, to remove the unconverted reactants and salt, drying with anhydrous sodium sulfate and distilling off the ether.

That the compounds provided by the invention have the indicated structure was demonstrated by analyzing a sample of tertiary-butyl Z-tertiarybuty1peroxy-2-methylpropanesulfonate, prepared in the above manner from the crude sulfochlorination product of di-tertiarybutyl peroxide (prepared in the manner described in Example I) and separated from the mixed reaction products as indicated after they had been maintained at the reaction temperature for one hour. The following analysis indicated the product to have the formula CizHzeOss and the structure,

CH3 CH3 CH3 Theory for Found CHHNOGS Per Cent Carbon 48. 48. 2 48.4 Per Cent Hydrogen S. 9, 8. 8 8.7 Per Cent Sulfur 9. G, 9. 5 10.7 n 1. 4350 i.

It was found that employing a catalytic amount of this compound in an emulsion polymerization of vinyl chloride initiated the reaction.

Example III and decomposes, upon heating, into free radicals having a variety of structures.

Example I V Tertiary-butyl 2(a,a dimethylbenzylperoxy) 2-phenylpropanepersulfonate is prepared by dissolving 18 grams of 2 (11,11 dimethylbenzylperoxy) -2-phenylpropanesulfonyl chloride in cc. of ether and adding the resulting solution to 5 grams of the sodium salt of tertiary-butyl hydroperoxide suspended in 50 cc. of ether while maintaining the reactant, during mixing, at 10 C. The persulfonate is isolated by extracting the mixed reaction products with water to remove the unconverted reactants and salt, drying and distilling oif the ether.

The product has the formula,

and decomposes, upon heating, into free radicals having a variety of structures.

The invention claimed is:

l. Tertiary butyl Z-tertiary butylperoxy 2- methylpropanepersulfonate.

2. Alpha,alpha-dimethylbenzyl 2-(chloro-tertiary butylperoxy) 2 chloromethylpropanepersulfonate.

3. Tertiary butyl 2 (alpha,alpha dimethylbenzylperoxy) -2-phenylpropanepersu1f onate.

l. A tertiary-alkyl ester of a persulfonic acid in which the persulfo group replaces a hydrogen atom of a di-tertiary-alkyl peroxide.

5. An ester in which an organic radical, the first atom of which is a saturated carbon atom, replaces the ionizable hydrogen atom of a persulfonic acid, in which acid the persulfo group replaces a hydrogen atom of an organic peroxide containing the peroxy group directly connected to two saturated carbon atoms and of the class consisting of the hydrocarbon peroxides and the halogen-substituted hydrocarbon peroxides.

6. An ester of a persulfonic acid in which at least one persulfo group replaces a hydrogen atom of an organic peroxide containing the peroXy group directly connected to two saturated carbon atoms and of the class consisting of the hydrocarbon peroxides and the halogen-substituted hydrocarbon peroxides.

7. An ester of a persulfonic acid, in which acid the persulfo group replaces a hydrogen atom of an organic peroxide wherein the peroxy group is directly connected to two hydrocarbon groups containing tertiary carbon atoms by bonds to tertiary carbon atoms, in which ester a hydrocarbon group containing a tertiary carbon atom is directly linked to the peroxy group of the esterified persulfo group by a bond from a tertiary carbon atom.

FREDERICK F. RUST. ALAN R. STILES. WILLIAM E. VAUGHAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,467,280 Walter Apr. 12, 1949 

1. TERTIARY-BUTYL 2-TERTIARY-BUTYLPEROXY-2METHYLPROPANEPERSULFONATE. 